Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.21.1 (DNase)
7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Incubation of HeLa cells with the anticancer agent N-methyl-N-nitrosourea (MNU) results in: (a) depression of intracellular nicotinamide adenine dinucleotide levels; (b) stimulation of the chromatin-associated, chromosomal protein-modifying enzyme polyadenosine diphosphoribose [poly(ADP-ribose)] polymerase, which uses nicotinamide adenine dinucleotide as substrate; and (c) some fragmentation of cellular DNA. DNase treatment of HeLa nuclei in vitro also stimulates poly(ADP-ribose) polymerase activity, but not in nuclei derived from MNU-treated cells unless they have been subsequently incubated to allow for recovery from MNU damage. DNA polymerase activity is stimulated in vitro by poly(ADP) ribosylation of nuclear proteins. By using intact nuclei derived from MNU-treated HeLa cells, the repair via elongation of single-strand DNA breaks is demonstrated in vitro. This repair is dependent on DNA polymerase activity and is enhanced by adenosine diphosphate ribosylation of histones. Inhibition of poly(ADP-ribose) polymerase with nicotinamide results in extensive degradation of MNU-damaged DNA. Taken as a whole, these results suggest that poly(ADP-ribose) polymerase may play a role in the repair of alkylation damage to cellular DNA and that the inhibition of this enzyme in vivo might be exploited to potentiate the antitumor and carcinogenic activities of MNU.
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PMID:A putative role for nicotinamide adenine dinucleotide-promoted nuclear protein modification in the antitumor activity of N-methyl-N-nitrosourea. 19 15

Using eukaryotic cells that have been rendered permeable to exogenously supplied nucleotides, we have characterized the activity of the poly(adenosine diphosphoribose) (poly(ADPR)) synthesis system and compared it to the DNA synthesis complex. The synthesis of poly(ADPR) is dependent on the presence of NAD and Mg2+. It does not require ATP, NaF or a monovalent cation. It is inhibited by N-ethylmaleimide. The reaction product conforms to the nuclease susceptibilities expected for poly(ADP ribose) in that it is degraded by venom phosphodiesterase but not by DNAase of RNAase. A comparison of the effects of inhibitors of poly(ADPR) synthesis and DNA synthesis clearly distinguishes between the two enzymatic systems. Nicotinamide, 5-methyl nicotinamide, thymidine, 5-bromo deoxyuridine, adenosine diphosphoribose, caffeine and formycin all inhibit poly(ADPR) synthesis but not DNA synthesis. In contrast, araCTP, cytembena and phosphonoacetic acid all inhibit DNA synthesis but not poly(ADPR) synthesis. Addition of DNAase to the permeable cells causes a marked stimulation of poly(ADPR) synthesis. L cells in logarithmic growth were found to have high levels of activity of the DNA synthesis complex and low levels of activity of the poly(ADPR) synthesis system. In contrast, cells at plateau phase density demonstrate a decrease in the activity of the DNA synthesis complex and a marked increase in activity of the poly(ADPR) synthesis system. When examined in the presence of added DNAase, the activity of the poly(ADPR) synthesis system is the same in cells obtained from log or plateau phase cultures. This indicates that the physiologic activity of the enzyme varies while the total amount of enzyme remains constant. When the permeable cells are allowed to synthesize both poly(ADPR) and DNA simultaneously, the synthesis of one polymer has no effect on the rate of synthesis of the other.
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PMID:Characterization and comparison of poly(adenosine dephosphoribose) synthesis and DNA synthesis in nucleotide-permeable cells. 20 14

A microhaemagglutination test in disposable U plates has been devised for rapid, quantitative evaluation in antistreptococcal antibodies in human sera. Fresh or freeze-dried glutaraldehyde-treated sheep erythrocytes sensitized with over fifteen extracellular proteins released by group A Streptococcus pyogenes including streptolysin O, deoxyribonucleases, hyaluronatelyase, streptokinase and nicotinamide dinucleotide glycohydrolase were used. Haemagglutination and anti-streptolysin O (ASLO) titers were determined in parallel on 434 serum specimens from 123 healthy subjects ("controls") and 311 patients with a history of supposed or evident streptococcal infection. The titration of the four above-mentioned anti-enzyme antibodies has also been made on about 100 sera from both groups. Haemagglutination titre (HT) was less than 800 in control sera. By contrast it was greater than 800 up to 12 800 in patients specimens. Very good correlation was found between HT on the one hand and ASLO or anti-SK, anti-HA and anti-NADase antibodies on the other hand. HT and anti-DNase B antibodies were less correlated. Haemagglutination titres appear to rise earlier than serological titres of conventional streptococcal antibodies. The haemagglutination test described may be particularly helpful as a rapid serologic indicator of streptococcal infections and more reliable than the titration of ASLO alone, or of any one of anti-enzyme antibodies.
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PMID:[Assay of human anti-exoproteins to group A streptococci by microhaemagglutination: correlation with anti-streptolysin O and various anti-enzymes (author's transl)]. 21 92

1. The isolated nuclei of the slime mould Physarum polycephalum contain an enzyme that will incorporated [adenine-3H] NAD+ into an acid-insoluble product, which is shown to be poly(ADP-ribose). 2. This incorporation has an optimum pH of 8.2 and a temperature optimum below 10degreesC. 3. Optimum stimulation is given by 15 mM-Mg2+. 4. 2-Mercaptoethanol or dithiothreitol also stimulates the incorporation, the latter at an optimum concentration of about 1 mM. 5. Under optimum conditions the Km value for the reaction is 0.28 mM at 15degreesC. Nicotinamide inhibits the incorporation with a Ki of 5.7 muM. 6. Exogenous DNA stimulates the incorporation by about 100%. 7. Preincubation of the nuclei with deoxyribonuclease, but not with ribonuclease, almost completely inactivates the incorporation of NAD+. 8. The enzyme is unstable at both 0degrees and 15degreesC in the absence of dithiothreitol. The presence of dithiothreitol at a concentration of 1 mM stabilizes the enzyme at both these temperatures. 9. The activity of this enzyme per nucleus was shown in three separate experiments to fall by about one-half in early S phase and then to rise to its pre-mitotic value after about 3 h, that is in late S phase. 10. The possible physiological function of this enzyme system is discussed.
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PMID:Poly(adenosine diphosphate ribose) polymerase in Physarum polycephalum. 23 97

A new type of nicotinamide adenine dinucleotide glycohydrolase (NADase) has been isolated from rat liver nuclei. When partially purified chromatin is passed through a Sephadex G-200 column in the presence of 1 M NaCl, enzyme activities catalyzing the liberation of nicotinamide from NAD elute in two peaks. One, which appears in the void volume fraction, hydrolyzes the nicotinamide-ribose linkage of NAD to produce nicotinamide and ADP-ribose in stoichiometric amounts. This activity is not inhibited by 5 mM nicotinamide. The other, which elutes much later, catalyzes the formation of poly(ADP-ribose) from NAD and is completely inhibited by 5 mM nicotinamide. The former, NADase, is DNase-insensitive and thermostable, has a pH optimum of 6.5 to 7, a Km for NAD of 28 muM, and a Ki for nicotinamide of 80 mM, and hydrolyzes NADP as well as NAD. The latter, poly(ADP-ribose) synthetase, is sensitive to DNase treatment and heat labile, has a pH optimum of 8 to 8.5, a Km for NAD of 250 muM and a Ki for nicotinamide of 0.5 mM and is strictly specific for NAD. Further, the former NADase is shown to lack transglycosidase activity, which has been documented to be a general property of NADases derived from animal tissues. These results indicate that the NAD-hydrolyzing enzyme newly isolated from nuclei is a novel type of mammalian NADase which catalyzes the hydrolytic cleavage of the nicotinamide-ribose linkage of NAD.
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PMID:Nicotinamide adenine dinucleotide glycohydrolase from rat liver nuclei. Isolation and characterization of a new enzyme. 24 Aug 31

Hemolytic mutants of Lancefield strain SS-95 and ATCC 19615 Streptococcus pyogenes were produced by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. These mutants contained the same levels of streptolysin O, nicotinamide adenine dinucleotidase, deoxyribonuclease, and hyaluronidase. The mutants were deficient in streptolysin S, as was the naturally occurring nonhemolytic Lowry strain. The mutants retained their pathogenicity for mice and, when reisolated from the dead animals, produced the mutant hemolytic pattern.
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PMID:Hemolytic mutants of group A Streptococcus pyogenes. 34 36

The effects of oxidative stress on DNA damage and associated reactions, increased polyadenosine diphosphate-ribose polymerase (PARP) activity and decreased nicotinamide adenine dinucleotide (NAD) and adenosine triphosphate (ATP) contents, have been tested in primary cultures of porcine aortic endothelial cells. The cells were treated with 50-500 microM H2O2 for 20 min or 100 microM paraquat for 3 days or were exposed to 95% O2 for 2 and 5 days. The administration of 250-500 microM H2O2 resulted in a marked increase in PARP activity and a profound depletion of ATP and NAD. Although hyperoxia had no effect on PARP activity and reduced only slightly the ATP and NAD stores, it markedly reduced the ability of endothelial cells to increase PARP activity upon exposure to DNase. Paraquat had a similar effect. Human dermal fibroblasts were also exposed to 50-500 microM H2O2 for 20 min or 95% O2 for 5 days. Their response to H2O2 differed from that of endothelial cells by their ability to maintain the ATP content at a normal level. Fibroblasts were also insensitive to the effect of hyperoxia. These results suggest that the oxidant-related DNA damage is a function of the type of oxidative stress used and may be cell-specific.
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PMID:Differential effects of hyperoxia and hydrogen peroxide on DNA damage, polyadenosine diphosphate-ribose polymerase activity, and nicotinamide adenine dinucleotide and adenosine triphosphate contents in cultured endothelial cells and fibroblasts. 250 Apr 51

Extraction of rat kidney cytosol with 10% charcoal at 4 C inactivated specific T3 binding. The decreased T3 binding in extracted cytosol could be restored by addition of boiled kidney cytosol. Three different factors (a, b, and c) which could increase T3 binding were identified by Sephadex G-50 column chromatography of boiled cytosol. Two factors (b and c) were eluted as relatively small molecules. Factor a was present in small amounts. Factor c was neutralized by incubation with EDTA, but factor b was not. Factor b was not destroyed by trypsin, protease, DNase, or RNase, but was destroyed by alkaline phosphatase. Factor b was destroyed by incubation with nicotinamide adenine dinucleotide phosphate (NADPH)-dependent glutathione reductase in the presence of oxidized glutathione. Although T3 binding to charcoal-extracted cytosol protein was not influenced by reduced glutathione or dithiothreitol, it was markedly increased by NADPH. Maximal activation induced by 50 microM NADPH was not further increased by further addition of endogenous factor b. The elution position of NADPH in gel chromatography corresponded to the elution position of factor b. Factor b or NADPH increased maximal binding capacity without changes in affinity constant. These observations suggest that T3-binding protein in cytosol is present in inactive and active forms and that the active form is generated by NADPH, which is present as one of the activators in cytosol. The effect of these cytosolic T3-binding proteins on nuclear T3 binding in vitro was also studied. In the absence of cytosolic T3-binding protein, [125I]T3 binding to nuclear receptor was decreased by unlabeled T3 in a concentration-dependent manner. In the presence of inactive form of cytosolic T3-binding protein, nuclear [125I]T3 binding was slightly diminished. In the presence of NADPH and cytosolic T3-binding protein, however, the amount of [125I]T3 bound to nuclei markedly decreased, which was associated with an increase of cytosolic [125I]T3 binding. NADPH alone did not influence nuclear T3 binding. These results suggest that T3 binding to nuclear receptor is regulated by an active form of cytosolic T3-binding protein in vitro.
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PMID:Active and inactive forms of 3,5,3'-triiodo-L-thyronine (T3)-binding protein in rat kidney cytosol: possible role of nicotinamide adenine dinucleotide phosphate in activation of T3 binding. 301 55

Membrane-envelope fragments have been isolated from Escherichia coli by comparatively mild techniques. The use of DNAase, RNAase, detergents, sonication, lysozyme, and ethylenediaminetetraacetate were avoided in the belief that rather delicate, but metabolically important, associations may exist between the plasma membrane and various cytoplasmic components. The membrane-envelope fragments have been characterized in terms of their content of major chemical components as well as their electron microscope appearance. Fractions containing membrane-envelope fragments were found to possess appreciable DNA- and protein-synthesizing activities. The fragments were rich in membrane content as determined by reduced nicotinamide adenine dinucleotide (NADH) oxidase activity and deficient in soluble components as measured by NADH dehydrogenase activity. The particulate fraction obtained between 20,000 g and 105,000 g and usually considered a ribosomal fraction was rich in membrane content and had a relatively high capacity for DNA synthesis. Envelope fragments sedimenting at 20,000 g attained very high levels of incorporation of amino acids into protein.
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PMID:Respiration and protein synthesis in Escherichia coli membrane-envelope fragments. IV. Chemical and cytological characterization and biosynthetic capabilities of fragments obtained by mild procedures. 433 49

A comparison between the results of the streptozyme hemagglutination test and serological titers for anti-streptolysin O (ASO), anti-hyaluronidase (AH), anti-deoxyribonuclease B (ADN-B), and anti-nicotinamide adenine dinucleotidase (ANAD) was made in two groups of human sera. In one group, serological titers for all the four antibodies were lower than the threshold of sensitization reported by the producing firm. In the second group, the titer of at least one of the four antibodies was equal to or higher than the threshold. False-positive and false-negative reactions occur with those sera when one or more antibody titer is at or near the threshold of the test as described by the manufacturer. The test was positive for all sera where either the ASO was greater than 166 or the ANAD was greater than 270, and for 98% of the sera with ADN-B greater than 360. It is, therefore, concluded that the streptozyme test can be used as an adjunct to the clinical diagnosis of streptococcal infections and their nonsuppurative sequelae. It is less useful to assess the levels of antibodies in sera from general population surveys. For such sera, the relative specificity and sensitivity of the test might yield misleading results. Until more experience is gained with the test, caution should be used in its application to infant and older adult age groups, where significant streptococcal antibody titers are frequently near the threshold of the test.
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PMID:Specificity and sensitivity of the streptozyme test for the detection of streptococcal antibodies. 436 57


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